Hit one of those "argh" moments in the VoIP project today. We import CDR files from a backend system. I read the field names and didn't see anything that looked like "destination" (in the sense of a physical location, like a city). So, we write a little subsystem that can guess location from phone number based on the same rule-set as the backend uses. Then we write an editor that lets you upload those rule-sets, revert them, comment them, and generally manage them. Then we integrate that into the importer.

Then the client points out that the data is in the record, it's just stored in a weirdly-named field as part of a big block of formatted text. Sigh. Sigh. Sigh. Sigh. (Yes, that was a 4-sigh event).